Use python3 explicitly

Will use python2 on opensuse, ubuntu, anywhere otherwise.
Merge pull request #4 from Kondou-ger/master

Use python3 explicitly.
Avoid cryptic messages when there are no arguments
Merge pull request #6 from Kondou-ger/no_cryptic_messages_without_args

Avoid cryptic messages when there are no arguments
Print argparsers help instead of my own help.
Only import what's necessary.
Add MIT-License
Fix AppTemplateAdvanced
Merge pull request #8 from Raydiation/add_mit_license

Add MIT-License
Merge pull request #9 from kabum/patch-2

Fix AppTemplateAdvanced
Merge pull request #7 from Raydiation/only_import_whats_necessary

Only import what's necessary.
Use choices in argparser and follow DRY.
Make FileExistsError less cryptic
Merge pull request #11 from Raydiation/prettify_FileExistsError

Make FileExistsError less cryptic
Merge pull request #10 from Raydiation/choices_and_DRY

Use choices in argparser and follow DRY.
remove trailing whitespaces